Herb: Smartweed

Latin name: Polygonum hydropiper

Synonyms: Persicaria fastigiatoramosa, Persicaria hydropiper, Polygonum fastigiatoramosum, Polygonum maximowiczii

Family: Polygonaceae (Buckwheat Family)

Medicinal use of Smartweed:

Smartweed has a long history of herbal use, both in Eastern and Western herbalism. It is not used very often, and is seen more as a domestic remedy being valued especially for its astringent properties which makes it useful in treating bleeding, skin problems, diarrhoea etc. The leaves are anti-inflammatory, astringent, carminative, diaphoretic, diuretic, emmenagogue, stimulant, stomachic, styptic. They contain rutin, which helps strengthen fragile capillaries and thus helps prevent bleeding. Use with caution. The seed is carminative, diuretic and stimulant. The whole plant, either on its own or mixed with other herbs, is decocted and used in the treatment of a wide range of ailments including diarrhoea, dyspepsia, itching skin, excessive menstrual bleeding and haemorrhoids. A poultice of the plant is used in treating swollen and inflamed areas. In Chinese tests, the plant was ranked 20th in a survey of 250 potential antifertility drugs. A homeopathic remedy is made from the leaves. It is used in the treatment of piles, menstrual pains and other menstrual complaints.

Description of the plant:


75 cm
(2 feet)

July to

Habitat of the herb:

Shallow water in ponds, ditches etc and in wet places on land.

Edible parts of Smartweed:

Leaves and stems - raw or cooked. They can also be made into an acid peppery condiment. They are very hot. The leaves contain about 7.5% protein, 1.9% fat, 8% carbohydrate, 2% ash. The leaves are said to contain rutin. Seed - raw or cooked. It is rather small and fiddly to utilize. The seed is used as a condiment - a pepper substitute. The sprouted seeds or young seedlings can be used as a garnish or added to salads, they are commonly sold in Japanese markets. They are very hot.

Other uses of the herb:

A yellow-gold dye is obtained from the stalks.

Propagation of Smartweed:

Seed - sow spring in a pot standing in water or in situ. Germination is usually free and easy. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer if they have reached sufficient size. If not, overwinter them in a cold frame and plant them out the following spring after the last expected frosts.

Cultivation of the herb:

Shallow water in ponds, ditches etc and in wet places on land.

Known hazards of Polygonum hydropiper:

Although no specific mention has been made for this species, there have been reports that some members of this genus can cause photosensitivity in susceptible people. Many species also contain oxalic acid (the distinctive lemony flavour of sorrel) - whilst not toxic this substance can bind up other minerals making them unavailable to the body and leading to mineral deficiency. Having said that, a number of common foods such as sorrel and rhubarb contain oxalic acid and the leaves of most members of this genus are nutritious and beneficial to eat in moderate quantities. Cooking the leaves will reduce their content of oxalic acid. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition.

Plant information taken from the Plants For A Future.